In these years, a memory card mounting a flash memory, a nonvolatile memory, expands its market as a recording medium for a digital camera and a mobile phone. In addition, the number of files which can be recorded in the memory card also increases with a capacity increase of the memory card. A data amount of FAT file system information required to handle the memory card accordingly has been increasing in a host device, and, as a result, a data amount of the FAT file system information transmitted and received between the memory card and the host device has been increasing.
Patent document 1 cites a problem that writing performance of data other than the FAT file system information deteriorates in a case where the data amount of the FAT file system information is large. In Patent document 1, a memory card controller for managing a file system structure based on the FAT file system information is provided in the memory card to handle the problem. This can reduce a frequency of the transmission and reception of the FAT file system information between the memory card and the host device. In Patent document 1, proposed is a memory card that prevents data reading and data writing performances from deteriorating in this way.
The networking of devices is progressing, however, conventionally only the host devices connect to the network. Now, a nonvolatile memory device (storage device), including the memory card, able to connect to the network is retailed as a commercial product.
Patent document 2 shows an example of using the storage device having this wireless communicating function as a home server. However, the storage device in patent document 2 does not manage a file system structure as in Patent document 1. It can be expected that a memory card which is able to connect to the network and manages a file system structure will be increased.
Patent document 1: Japanese Unexamined Patent Publication No. 2003-187203
Patent document 2: Japanese Unexamined Patent Publication No. 2002-199121